Multiplexing techniques in Computer Networks - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Time Division Multiplexing (TDM)

Which statement best describes how Time Division Multiplexing (TDM) works?

A It assigns different time slots to multiple signals over the same channel sequentially.

B It divides the total bandwidth into frequency bands assigned to each user simultaneously.

C It combines signals by varying the amplitude of a carrier wave for each user.

D It sends multiple signals by encoding them into different polarizations of a wave.

💡 Hint

Think about how signals share the same channel but take turns in using it.

Time Division Multiplexing (TDM) works by dividing the channel into time slots. Each user transmits in their assigned time slot, one after another, sharing the same frequency but at different times.

📋 Factual

intermediate

Frequency Division Multiplexing (FDM) Characteristics

Which of the following is a true characteristic of Frequency Division Multiplexing (FDM)?

A It divides the channel bandwidth into non-overlapping frequency bands for each user.

B It requires synchronization of time slots between users.

C It uses digital encoding to separate signals in the time domain.

D It combines signals by changing the phase of a carrier wave.

💡 Hint

Consider how different users can transmit simultaneously without interfering by using different parts of the spectrum.

Frequency Division Multiplexing (FDM) splits the total bandwidth into separate frequency bands. Each user transmits simultaneously on their own frequency band without overlapping.

🔍 Analysis

advanced

Comparing TDM and FDM Efficiency

Given a communication channel shared by multiple users, which multiplexing technique is generally more efficient when users have bursty data transmissions and why?

A TDM, because it allocates fixed time slots regardless of user activity, ensuring fairness.

B FDM, because it allows users to transmit simultaneously without waiting for time slots.

C TDM, because it can dynamically assign time slots only when users have data to send.

D FDM, because it uses digital encoding to compress data and save bandwidth.

💡 Hint

Think about how time slots can be assigned flexibly versus fixed frequency bands.

Dynamic TDM can assign time slots only when users have data, making it efficient for bursty traffic. Fixed FDM allocates frequency bands continuously, which can waste bandwidth if users are inactive.

🚀 Application

advanced

Identifying Multiplexing Technique from Scenario

A cable TV provider sends multiple TV channels over a single coaxial cable. Each channel occupies a specific frequency band and all channels are transmitted simultaneously. Which multiplexing technique is used here?

A Code Division Multiplexing (CDM)

B Frequency Division Multiplexing (FDM)

C Time Division Multiplexing (TDM)

D Wavelength Division Multiplexing (WDM)

💡 Hint

Think about how different TV channels can be sent at the same time without interfering.

Cable TV uses Frequency Division Multiplexing (FDM) by assigning each channel a unique frequency band, allowing simultaneous transmission over the same cable.

❓ Reasoning

expert

Multiplexing Technique Selection for Optical Networks

In an optical fiber network, multiple data streams are sent simultaneously by using different wavelengths (colors) of light. Which multiplexing technique is this, and why is it preferred over TDM or FDM in this context?

A Code Division Multiplexing (CDM), because it encodes light signals with unique codes.

B Time Division Multiplexing (TDM), because it allows precise timing control of light pulses in fiber.

C Frequency Division Multiplexing (FDM), because it divides the optical spectrum into frequency bands like radio waves.

D Wavelength Division Multiplexing (WDM), because optical fibers can carry multiple wavelengths simultaneously with minimal interference.

💡 Hint

Consider how light properties are used to carry multiple signals in fiber optics.

Wavelength Division Multiplexing (WDM) uses different light wavelengths to send multiple signals simultaneously through the same fiber. It is preferred because optical fibers support many wavelengths with low interference, unlike TDM or FDM which are less practical for light signals.